From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D6D87346E7A; Thu, 13 Nov 2025 12:39:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763037549; cv=none; b=splelaS/EIy/i7sUxA2+c1wX6VoWHSFUrXMpY2sktgsN8QXeV0PR/Umm1C2jkXaai4TYpyhP8xx67muoEy3YlZjPSsWnTfuetF8WDHhNoiWRDaZbcNqp7KPtEidF9Ie4d2U+RW0dbk0PLdPJ05k/Obx99+uTvXBpsAP9cxR9FOs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763037549; c=relaxed/simple; bh=ZgPgafOsTrCHIaMoJUIubdvBowQLIX9k8MopM5ZtCBk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Z/WGlIW1bQSwf9WwZuORRi9RnzU3FpquVa4Fme9BZ/iMePG8RU7ccxna3uqV4gCqp83bTY2waVUpvQUNT1HSFKApPdEQK7NtKntcplSND1glpJIUVQ74rAA0Q1EA5LLqRF6gfnLlmXv2M6gG95EouRcGT/u28jol96p8mdkz47Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eRPlbQ/e; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eRPlbQ/e" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A25FC4CEF5; Thu, 13 Nov 2025 12:39:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763037549; bh=ZgPgafOsTrCHIaMoJUIubdvBowQLIX9k8MopM5ZtCBk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eRPlbQ/eRkdKWHi0XtaoJ7Boq++k7y7xE69bxtEDqm+v1VSHl0Ic1dxd/kSoMRQu6 jPe/aLAnzzqZ/L/9omGuY4rX7hXsV4EAiL9KPhYGeFEiyDJM2jasZOFcjVQOhYe2x+ OS/eLzMeCKBjuN9QiNfpAC6ImAnDvaDyCvqOyKzXCdUq1+RWm9tawpYYRDx54j8GJB Ccbpm6GhG6RLLLtFacBEtwcdWMWVCyIbblPDGI5SUc540oXkfufTtuRTL4VbNWNnNR ELiFR49w0IhbAxU3AHuDgYkT9J5Q0j87VnEboXmhoKy8R6GxCxtwTModpqwvOK+jK0 aa/pOqQhRRiMA== From: Jiri Olsa To: Steven Rostedt , Florent Revest , Mark Rutland Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Menglong Dong , Song Liu Subject: [PATCHv2 bpf-next 4/8] ftrace: Add update_ftrace_direct_del function Date: Thu, 13 Nov 2025 13:37:46 +0100 Message-ID: <20251113123750.2507435-5-jolsa@kernel.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251113123750.2507435-1-jolsa@kernel.org> References: <20251113123750.2507435-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Adding update_ftrace_direct_del function that removes all entries (ip -> addr) provided in hash argument to direct ftrace ops and updates its attachments. The difference to current unregister_ftrace_direct is - hash argument that allows to unregister multiple ip -> direct entries at once - we can call update_ftrace_direct_del multiple times on the same ftrace_ops object, becase we do not need to unregister all entries at once, we can do it gradualy with the help of ftrace_update_ops function This change will allow us to have simple ftrace_ops for all bpf direct interface users in following changes. Signed-off-by: Jiri Olsa --- include/linux/ftrace.h | 6 +++ kernel/trace/ftrace.c | 99 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 105 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index ded3a306a8b2..433c36c3af3b 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -543,6 +543,7 @@ int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr); int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash); +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash); void ftrace_stub_direct_tramp(void); @@ -575,6 +576,11 @@ int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash) return -ENODEV; } +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) +{ + return -ENODEV; +} + /* * This must be implemented by the architecture. * It is the way the ftrace direct_ops helper, when called diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0b6e1af8f922..3dd1e69aceca 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6376,6 +6376,105 @@ int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash) return err; } +/** + * hash_sub - substracts @b from @a and returns the result + * @a: struct ftrace_hash object + * @b: struct ftrace_hash object + * + * Returns struct ftrace_hash object on success, NULL on error. + */ +static struct ftrace_hash *hash_sub(struct ftrace_hash *a, struct ftrace_hash *b) +{ + struct ftrace_func_entry *entry, *del; + struct ftrace_hash *sub; + int size, i; + + sub = alloc_and_copy_ftrace_hash(a->size_bits, a); + if (!sub) + goto error; + + size = 1 << b->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + del = __ftrace_lookup_ip(sub, entry->ip); + if (WARN_ON_ONCE(!del)) + goto error; + remove_hash_entry(sub, del); + kfree(del); + } + } + return sub; + + error: + free_ftrace_hash(sub); + return NULL; +} + +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) +{ + struct ftrace_hash *new_hash = NULL, *filter_hash = NULL, *free_hash = NULL; + struct ftrace_func_entry *del, *entry; + unsigned long size, i; + int err = -EINVAL; + + if (!hash_count(hash)) + return 0; + if (check_direct_multi(ops)) + return -EINVAL; + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EINVAL; + if (direct_functions == EMPTY_HASH) + return -EINVAL; + + mutex_lock(&direct_mutex); + + /* Make sure requested entries are already registered. */ + size = 1 << hash->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { + del = __ftrace_lookup_ip(direct_functions, entry->ip); + if (!del || del->direct != entry->direct) + goto out_unlock; + } + } + + err = -ENOMEM; + filter_hash = hash_sub(ops->func_hash->filter_hash, hash); + if (!filter_hash) + goto out_unlock; + + new_hash = hash_sub(direct_functions, hash); + if (!new_hash) + goto out_unlock; + + /* If there's nothing left, we need to unregister the ops. */ + if (ftrace_hash_empty(filter_hash)) { + err = unregister_ftrace_function(ops); + /* cleanup for possible another register call */ + ops->func = NULL; + ops->trampoline = 0; + ftrace_free_filter(ops); + ops->func_hash->filter_hash = NULL; + } else { + err = ftrace_update_ops(ops, filter_hash, EMPTY_HASH); + } + + if (!err) { + free_hash = direct_functions; + rcu_assign_pointer(direct_functions, new_hash); + } + + out_unlock: + mutex_unlock(&direct_mutex); + + if (free_hash && free_hash != EMPTY_HASH) + call_rcu_tasks(&free_hash->rcu, register_ftrace_direct_cb); + if (filter_hash) + free_ftrace_hash(filter_hash); + + return err; +} + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ /** -- 2.51.1